Radio receiving apparatus



May l, 1928.

E. E. CLEMENT ET AL RADIO RECEIVING APPARATUS Filed July 8. 1924Patented May 1, 1928.

UNITED STATES NParr-:NT orrlcs.

EDWARD E. CLEMENT HARRY E. LOWIEINSTEIN-y OF WASHINGTON, DISTRICT Ol'COLUMBIA, ASSIGNOBS TO EDWARD F. COLLADAY,

COLUMBIA.

0F WASHINGTON, DISTRICT 0F RADIO l2R11?.CIEIVINGt APPARATUS.

Appucanm med July 3,1924. serial no. 724,886.

van improvement over that described and,

claimed in Letters Patent No. 1,522,308, granted to us January 6, 1925.

In said patented system we provide a test or listening relay at thesubscribers station,

' connected to the telephone wire circuit and controlled by a radiooperator at central to connect thesubstation radio receiving apparatusor circuits to the wire circuit for telephonie transmission thereover to'central,f

whereby thesaid radio `operator may listen to the actual sounds receivedand reproduced at the'substation while broadcasting, with a view to theregulation and adjustmentof the transmitting instrument `or thereceiving instrument, or both. In the present case, we provide for suchsupervision by connecting a telephone transmitter to the contacts of thelistening relay, and so relating said transmitter to the 'receiver orloud speaker'of the radio receivin set that direct mechanical conductiono sound waves takes place between them, and atest of the completeperfomance ofthe vapparatus as a whole is possible. I

Our invention is illustrated in the accompanying drawings,.in which Fig.1 is a diagram showin lice having a tele hone switc acentralfofboard.and a radio switchboar a subscribers 'stationequipped with a. telephoneand a radio 'receiving set, and the ine circuit therefrom to central.

Fig. 2 is a modification of the subscribers loud speaker and audiosupervisory means.

Fig. 3 is a side view of the combined loud slpeaker and vtelephonetransmitter' shown iagrammatically inFig. 1. r

Referring to the drawings, C is the central oice which for convenienceis shown equip ed with manual apparatus, but which may ave automaticswitching apparatus, `for the interconnection of telephone lines, or forthe radio station control, or both. The line 16--17 is connected asusual to terminals on the telephone switchboard and to one or moremultiple terminals on the radio switchboard, where the radio operatorhas cord circuits typified at Px, equipped with a switch Kx forconnecting battery to the tip side of line, the cut o'- relay of theline being at the same time energized teclear said side ofrground at thecentral office, Vwhich is normally connected through the windings of theline relay.

At the substation A, the telephone T is a standard common batteryinstrument set. The radio receiving apparatus is equipped with anothertelephone set, comprising a transmitter-T', receiver t', induction coilI, switch H and condensers g3, g, The radio set in itself forms no partof the present invention, but to supply a loud speaking horn for ourpurposes, is shown as having a detector tube 30, and two stages of audioamplitication by ltubes 31 and 32.. The usual transformers 3334, 35 areprovided,A with batteries A and 'B for filaments and plates..

Thehorn 36 and the switch H are so related that when the telephone T isturned up to open the switch H it will be in position to receive soundwaves from the horn. When the switch H is closed-it closes the filamentcircuits as follows: A', 25, 42, H', 41, filathe radio operator atcentral can close 'the filament circuit and also the circuit oftransmitter T by energizing relay L5. For this purpose,2key KX isclosed, and battery current Hows' over tip side 16 of line to the pments, battery. When the switch is open,

substation, thence through` back -contact of cut of `relay L 4 by wire26 to Ls and round. Ll5 becoming energized, closes the fo lowingcircuits: filament circuit from A', 25, 27 37,

43; transmitter circuit from A to 25, 27", T',

I, and back to battery, shown as by ground return, but may be by wire;line transmission circuit: 16, contact of L, 26, 27, 39, q,

t', -I q, 40, 27", .back contact of L, and so to sleeve'side 17 of line.The operator thus controls both the filament circuit and *the repeatback circuit, and may receive the actual-sound waves produced b the loudspeaker, by transmission throng the bod or frame of the horn thereotland throug the arm of the transmitter T joined to the horn at J 2 (seeFig. 3). The arrangement of this transmitter arm 1t will be noted, issuch as to permit the transmitter itself to be used when desired as amute to muiie the i sound proceeding from the horn. The mech-anicalstructure of this device vis best shown in Fig. 3 where T indicates thetrans` mitter and J2 represents the hinged joint made with firmconnection between its. relatively movable partito render it agoodconduotor of sound vibration. In this form, we provide switch H inthe form of a push button with normal open contact arranged to be closedb the transmitter when pushed down into tie dotted line position, inwhich osition it will be noted the transmitter may e employed bythesubscriber for ordinary telephonic purposes. The transmitter may also bethus employed without closing the contacts of switch H by adjusting thearm in an intermediate position.

Fig. 2 shows a modification in which the transmitter T is permanentlysecured by rigid mechanical means on the neck ofthe horn 36, so thatsound vibrations may be `directly communicated to the transmitter.

In this case the switch H may remain in the form shown in our patent butwould have to be worked manually to close the filament circuits.

It is to be understood that the mechanical connection of the transmittermay be varie-d without departing from thc invention, as for example byconnecting it on a metal rod or other metal connection to the base orsource of vibration of the loud speaker.

We claim:

1. A combined superaudio frequency and telephone transmission systemcomprising a receiving station, a supervising station there-l fore, anda telephone line interconnecting the two, a superaudio frequencyreceiving and detecting apparatus in said receiving station, vincludinga telephone receiver conyrier may be transmitted at audio or telephone'frequency over' the telephone line to the supervisory station.

2. In a -combined radio and telephone station, a radio receiving sethaving a receiver connected to its output circuit, a telephonetransmitter mechanically connected with the frame or shell of saidreceiver and movable thereon, and switching contacts receivercontrolling the operating circuits ot' said radio set andthemselvescontrolled in the movement of said transmitter on said receiver.

3. In a combined radio and telephone system comprising a receivingstation having a radio receiving set and a supervisor station connectedwith the receiving station by a telephone line, a receiver connected tothe output circuit of said radio set, a telephone transmittermechanically mounted on the Vframe or shell of said receiver so as to bemovable thereon into and out of operative position, switch contacts alsoon said receiver controllable in the movement of the transmitter foropening and closing the operating circuits of the radio set, and circuitconnecsions from said transmitter to said telephone In testimonywhereofwe hereunto aix our signatures.

HARRY F. LowENsTRIN. EDWARD R. CLEMENT.

also on said

